The following is an excerpt from How to Be Animal
(Penguin Random House, March 2021).
THE IDEA IS THAT we were not human and then we became human. And when we became fully human, we could no longer be understood as animals. This idea gained popularity in the decades after the publication of On the Origin of Species. As evidence of our early ancestors was found, thinkers and scientists started to focus their energies on defining the moment when we became human as we understand it today. The desire was for unique biological characteristics that could be dated after the emergence of our species.
By the early twentieth century it was widely considered among scholars that around 40,000 years ago, in an era referred to as the Upper Paleolithic, a cognitive leap occurred whereby groups of Homo sapiens in Western Europe began acting and behaving in a way that marked them out as human. The “Human Revolution,” as it became known, was talked about as an almost miraculous span of time in which a suite of skills such as abstract thinking, sophisticated tool use, language, and symbolic image-making arose among men and women, transforming people in an extraordinarily short timescale from an ape to a superbeing. If God hadn’t brought forth humans in a state of completeness, at least evolution had very nearly done so. But this source of reassurance soon hit difficulties.
If it was biological proofs of difference that mattered, how could we separate out biology from cultural behavior? In an age of smartphones, it is obvious to most of us now that cultural innovations can accumulate suddenly without any physical change to the people inventing them. It’s perfectly plausible that there was no human revolution, only some phases of rapid evolution and many phases of slow evolution. It’s also possible that the underlying cognitive abilities that gave rise to the cultural manifestations we’ve since labelled as “human modernity” were present tens of thousands of years before the speciation of Homo sapiens, let alone the arrival of the Neolithic era. As American archaeologist Sally McBrearty has since said: “The search for revolutions in Western thought has been, in part, a search for the soul, for the inventive spark that distinguishes humans from the rest of the animal kingdom.”
Alfred Wallace, who arrived at his own theories of evolution at more or less the same time as Darwin, understood the advantages of this for human psychological wellbeing. To revive our hopes for salvation, we could explain away the body as a natural event, but single out some essence that is the source of “a higher intelligence.” It is because of notions like this that modern secular individuals don’t need a unique soul. It is enough to believe that our elaborate cognition sets the boundary. The boundary in this sense is not between an immortal being and its physical body but consists of the superior qualities of human rationality. Human mental life consists of a range of capabilities that lift us out of nature.
This was particularly appealing to those who had inherited humanist ideas, sometimes of deeply compassionate intent, to place the interests of human persons at the center of judgement. According to secular humanism, perhaps other animals are sentient, even conscious by some measures, but they lack a sense of self, any knowledge of right or wrong. They lack a soulful mind. Experiences like pleasure were to be given intrinsic value, so that we could point to the duties that arise from this. In practice, all this did was to isolate human things and then use this to argue we only have duties to humans. It was a neat trick. Humanists had carved our statue and hidden the chisels with which it was made. While Enlightenment humanism did much to argue for science as the true expression of human power, science in its pursuit of minutiae has refused to toe the line. The evidence from science has continued to tell us that there’s no such thing as a human in this sense. The traits and appearances that define animals come about through processes. They’re neither an end point nor a scale. Most of the capacities we prize evolved gradually and would have been at least partially present in ancestors that today we would consider as without any special status whatsoever.
Ian Tattersall, a veteran taxonomist and curator emeritus at the American Museum of Natural History, is acutely aware that “biology doesn’t permit neat boundaries.” Yet history has proven many of us to be “reluctant to admit diversity.” It is more than possible that biological architecture can come before the behavior kicks in. Take language, for instance. For humanists, language is often held up as one aspect of the unique essence that makes us more than animal. Yet there’s great disagreement about the origins of language. Some of this comes down to how we define language. Among language specialists, Derek Bickerton sees true language as something that only emerged in Homo sapiens and as a “catastrophic event.” Tim Crow argues it was a speciation event, and Richard Klein that it may have come even later. But American linguist Ray Jackendoff is among a group of scholars that believe language developed incrementally, beginning around two million years ago at the onset of the Homo evolutionary branch.
For a long time, it was also presumed that other hominin species like Neanderthals died out because they didn’t possess skills like human language. Yet in I983 a hyoid bone was discovered among Neanderthal remains. The hyoid bone is a funny little horseshoe-shaped bit of our anatomy believed to be essential for complex speech. Some have argued that the bone might have come in handy for singing rather than speaking. But others believe the evidence points to speech. If possessing language is that which justifies our special status, then we must at least acknowledge it now looks likely that this wasn’t a Homo sapiens thing but a hominin thing. This is much more confusing. It may place the evolution of language back to a common ancestor. Recent analysis on dental specimens suggests that the two species diverged at least 800,000 years ago. Although gene flow continued between the two species, it muddies the waters if we hope for a pure source of exception. If we were to travel back in time to observe the first of our ancestors chatting together around a fire, we might see a bunch of hairy, heavily browed animals.
And there would probably be more humanlike animals than historians have cared to admit. In 20I9, a complete hominin cranium was recovered from Woranso-Mille in Ethiopia by African anthropologist Yohannes Haile-Selassie. It caused upset because, up to this point, it had been assumed that modern humans evolved in a direct line from Australopithecus anamensis and then Australopithecus afarensis. Yet the specimen revealed the likelihood that these two intelligent, upright primates overlapped with each other as separate species. Human evolution appears to be highly branched, not a straight arrow of descent. Haile-Selassie and others see this as evidence that our ancestors belonged to more general evolutionary trends to adapt to changes in climate and shortages of food. The same year, Russell Ciochon’s team successfully dated skeletal remains of Homo erectus in Ngandong in Java to around I08–II7,000 years ago. A human ancestor once thought to be a direct ancestor now looks to have overlapped with our own species too.
Nobody knows the full story yet, but the idea of revolutions softens a reality that is strange and disturbing to us. If language, as argued by someone like prehistorian Robert Bednarik, evolved gradually throughout the Pleistocene period, when did we suddenly cross some unbreachable line between us and other animals? Most of what we can see in the fossil record points to the slow stages that have led to everything we esteem in ourselves. The controversial jasperite cobble is a small piece of rock that looks like a human face. What makes it of interest is that it was found with the bones of an Australopithecus africanus individual in a cave in South Africa. It isn’t evidence for art, and we can’t prove it was deliberately in this animal’s possession. But how else did it get there? Jasperite isn’t found anywhere near this region. What if it was noticed by a being that wasn’t in the Homo branch of primates, and what if it was an object that meant something to this creature: a treasure?
This piece of jasperite is millions of years old. But by at least 800,000 years ago, it looks like hominins were discriminating between ordinary items and more exciting ones, like crystals. At this time, there are also possible signs of the symbolic use of pigment. Another compelling but uncertain object is the Tan Tan figurine from around half a million years ago. This seems to exploit visual ambiguity. A semi-weathered bit of a stone, it looks like a voluptuous woman. The shape is natural, but those who have studied it believe there’s evidence that the grooves that give it a human form were artificially exaggerated.
Photo: Ekkehart Malotki
The least controversial of such early indications of a more assertive consciousness comes from the creation of cupules around the world in the Lower Paleolithic. These are depressions in a rock surface, as if a small bowl has been set into it. They are made deliberately by percussion, using a hard object. Some specimens in the Kalahari Desert date from more than 400,000 years ago. Some may be even earlier. They are widely regarded by specialists in rock art as among the first efforts made by animals to express themselves symbolically. Often there are hundreds of them grouped together, like a close-up of the skin of a strawberry. A single cupule might require thousands of blows to make on hard rock. Pounding on stone takes time and energy. Why on earth did these beings do it?
Art historian Ellen Dissanayake believes these ritual marks stimulated the opioids in the brain that produce feelings of trust and security among small groups of individuals. Did the hammering sound like thunder or the hooves of a stampede? Did our ancestors sing along with the rhythm? Nobody knows. But these creatures would not only have been powerful predators themselves; they would also have been prey. Although they were not modern humans, whatever kind of mind they had was supple enough to begin ritual.
These glimmers of a complex truth matter. They matter because they show us that we are part of a gradual metamorphic act of life. The search for revolutions or for natural traits that belong exclusively to Homo sapiens is certainly of interest. But it is also a compulsion among those who need a solution to Darwinism. Gradualism makes morality less absolute, weakening the confident basis of our exclusive moral status. That the generations after Darwin hunted for signal markers so assiduously only exposes a deeper psychological basis to the search.
None of this is to say that we shouldn’t answer to the specific capacities of humans as we are today. In whatever way it was that we evolved, humans are remarkable and it seems right that we should respond to our particular needs. But why doesn’t it follow for the needs of other species too? How often do we dismiss the culture or language in other species as diverse as scrub jays and bottlenose dolphins? The work of evolutionary biologists like Andrew Whiten has revealed the extent to which other animals use social learning to mitigate nutritional stress. Chimpanzees, who have been known to use over thirty different kinds of tools, exploit natural hammer materials when their fruit diet is depleted in the dry season. Orangutans use a look-and-learn method between mothers and their children to pass along important survival tools, like using stems for getting at termites. Chimpanzees also fish for termites and have been seen donating tools to teach less able youths in their group, at a cost to themselves.
Photo: Mark Higgins
This is worth bearing in mind given that more than 60 per cent of primates are endangered because of our behavior. Since the I960s, populations of chimpanzees have dropped by a half. In the end, we do little to halt these losses because we believe in an absolute border between us and them. Their deaths are but a candle snuffed out. We forget that the recent ancestors to whom we owe our life would be dismissed by the same measures today.
Melanie Challenger works as a researcher on the history of humanity and the natural world, and on environmental philosophy. She is the author of On Extinction: How We Became Estranged from Nature (Counterpoint). She received a Darwin Now Award for her research among Canadian Inuit and the Arts Council International Fellowship with the British Antarctic Survey for her work on the history of whaling. She lives with her family in England.
- Purchase How to Be Animal.
- Read Melanie Challenger’s feature “Fear Itself” (Spring 2018 issue).
- Looking for more reading ideas? Consider Orion‘s recommendations.